To confirm that anti-ATCV-1 IgG1 isotypes associate with ALS patients, and to determine if intracranial ATCV-1 injection into SOD1G93A-transgenic mice hasten the onset or development of MND.

Environmental and infectious exposures associated with MND include WNV, poliovirus, HIV, and cyanobacteria [1]. Recently, preliminary serological data has shown that sera from ALS patients have significantly elevated IgG isotype antibody levels to Chlorovirus ATCV-1 compared with healthy subjects. Chloroviruses (CV), which naturally infect chlorella-like green algae but may be part of the human virome, have shown to infect mammalian macrophages, inducing inflammatory mediators

(IL-6) and apoptosis [2]. ATCV-1, one of more than 30 chlorovirus types, encodes its own SOD1, which may contribute to the clinical manifestations of ALS.

Serum samples were collected from 17 patients with ALS and 13 age matched controls. These samples underwent evaluation for IgG1, IgG2, IgG3, IgG4, IgA, and IgM antibodies directed against ATCV-1 and IL-6, using ELISA techniques. Additionally, 10 SOD1G93A-transgenic and 10 C57Bl/6 wild type mice were injected intracranially at 5weeks of age with 10⁶ infectious ATCV-1 virus particles or injected with an equal volume of saline.  The mice were monitored daily for development of motor dysfunction. Following euthanization, spleens will be analyzed for T cells and Treg activity.

The data obtained has identified heightened anti-ATCV-1 IgG1 subclass in ALS patients, compared to healthy controls. The time frame for onset of motor dysfunction in ATCV-1 infected SOD1G93A-transgenic mice was significantly accelerated when compared to uninfected transgenics.

 This study identified a significant association with time of disease onset and progression in ATCV-1 inoculated vs untreated SOD1 transgenics. This finding, together with the identified ATCV-1 IgG1 subclass association with ALS, suggests that chloroviruses, ubiquitous worldwide in fresh water aquatic environments and potentially part of a human virome, appear to be associated with the pathogenesis of ALS.